Improvement in electric fire-alarms



ments of the house or to a common wire,

UNITED STATES PATENT OFFICE.

EDWARD A. HILL, OF CHICAGO, ILLDTOIS.

IMPROVEMENT IN ELECTRIC FIRE-ALARMS.

Specication forming part of Letters Patent No. 121,717, dated December 12, 1871; antedated December 9, 1871.

To all whom it may concern:

Be it known that I, EDWARD A. HILL, of Chicago, in the county of Cook and State of Illinois, have invented certain Improvements in Automatic Electrical Fire-Alarms; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawing and the letters and figures of reference marked thereon which form part of this specification, and in which- Figure 1 is a rear view of the indicator and a sectional view of a partition-wall and ceiling, showing the arrangement of the wires and the mercury-connectors. Fig. 2 is a section on the plane ofthe line x a' in Fig. 1, looking toward the bell. Fig. 3 is a section on the plane of the line y y in Fig. 1, looking downward. Fig. 4 is a front View of the indicator and bell, and Fig. 5 a view of the mercury connector enlarged, its plasterof-Paris inclosing-shell being shown in section.

Like letters of reference made use of in the several gures indicate like parts.

A is an electric battery of the usual construction, and which is placed in any convenient position in the building to be tted with the automatic tire-alarm. The negative-wire electrode of this battery proceeds to all the various apartwhich connects all the various apartments. B7 are what I term. automatic mercurial connectors, one of which is shown enlarged at Fig. 5. This connector consists of a glass tube, b, with a bulb, c, from which is prolonged the bent tube b. This tube is partly lled with mercury, d, leaving a space above the mercury in the bulb, which is full of atmospheric air. The mercury also rises for a portion of the height of the tube b. The end of the tube I) is open, and two small wires, not in contact, pass into this open end and down to within a little distance of the upper surface of the mercury. These two small wires are so arranged that when connected a circuit is complete from the batteryA through an annunciator, to be hereinafter described. This automatic connecting device is inclosed in a hollow shell of pla'ster of Paris, c, and is held in place within said shell by means of a cork, j', through which the tube b passes. Now, when this connector isplaced within an apartment in the ceiling with the open end of the shell down, any unusual heat of the said apartment will be felt by the air in the tube. The heat, rising to the ceiling, will expand the air in the bulb c, which will force the mercury to rise in the tube b. If the heat be great enough the mercury will nally rise until it touches the small wires in the tube, when the circuit is completed through the said mercury, and an alarm given at the annunciator or indicator. One of the above-mentioned small wires sconnects with the common wire above described, while the other, s+, connects with a wire, 15+, which proceeds to the annunciator or indicator, and is attached to a helix placed around a soft-iron core, a. The opposite pole of this helix is connected, by a wire, o, to the common wire -l-a, which connects with the helix of an electro-magnet, D, the opposite pole of which helix is connected to the positive-wire electrode ofthe battery. E is the indicator, consisting of a face-plate, F, upon which are placed the names or numbers of the various apartments of the house. Gr is a shaft passing horizontally through the said plate F and having bearings in a frame-work, H. The outer end of this shaft is provided with a curtain, I, and the inner end with a permanent magnet, J, in the form of a bar. K is a rod furnished with clasps or bearings k, which slide upon the frame-work H. A jointed lever, L, connects `this rod with a crank or handle, M, at the front of the indicatorcase. Now, a motion of this crank slides the bar K along the frame-work H, and a projection or projections, m, engage the magnets J when hanging down, as seen at Fig. l, and lift them up, bringing the free ends in contact with the projecting end of the soft-iron core u. When in this position the attraction ofthe core to the magnet is sufficient to retain them together; and, also, when the magnets are in this position, the curtain or curtains 1 are swung down so as to cover the names or numbers upon the face-plate F.

When the wires at any particular one of the connectors B (say B) are reached by the mercury and the circuit thereby closed a current is sent from the battery through the electro-magnet D, which, by an ordinary mechanism, is made to ring a bell 5 from thence the current passes to the core u and around its helix, and so to the connector B', and from thence, by the common wire, back to the battery. The passage of the current through the helix of the core u converts it into an electro-magnet with a like polarity to the permanent magnet J, whereby the said magnet J is repelled; and this repulsion, conspiring with the weight of the said magnet, is sufficient to coun- 

